Also you can get more inspirations from JRPGs enemies, usually those games do a color palette swap, change a few stats and you have a new enemy that feels good haha.
About cleaning up the game, I usually see that people give the last day to just polish on small things or make the misc stuff like audio and more. I try to follow that but I can’t most of the time because the game main loop is still unfinished xD
And one thing once the jam ends, you can "redo" your game outside the theme limitation or you can grab your systems or what you liked from your game and put those on other ideas, so not everything is a loss once the jam ends :)